A silver halide color photographic material generally has silver halide emulsion layers each being sensitive to three primary colors of red, green and blue. The material is processed by a so-called subtractive color process of reproducing a color image where the three couplers in the respective emulsion layers yield colors which are complementary to the colors to which the respective layers are sensitive. The color image to be obtained by processing such a silver halide color photographic material is generally composed of an azomethine dye or indoaniline dye to be formed by reaction of the oxidation product of an aromatic primary amine color developing agent with a coupler. The color photographic image thus obtained is not always stable to light or wet heat. When it is exposed to light for a long period of time or it is stored under the conditions of high temperature and high humidity, the color image is often faded or discolored or the white background area thereof is often stained, so that the quality of the thus exposed or stored image is deteriorated.
On the other hand, various efforts have been made for the purpose of more faithfully reproducing the color of the object to be photographed. As one means, couplers which have a high coloring capacity and which may yield dyes of good hue have been developed. However, the dyes to be formed from most of the couplers do not have sufficient color fastness and especially the color fastness thereof to light is insufficient. In addition, staining of the white background area is large when these couplers are used. Therefore, such couplers are not practical.
Fading and discoloration of the color images which are formed are fatal drawbacks for recording materials. In order to remove the drawbacks, an anti-fading agent or a stain inhibitor have been used. For the purpose of preventing deterioration of the image quality due to ultraviolet rays, an ultraviolet absorbent has been used. In order to overcome the drawbacks discussed above, various means have been proposed.
Examples of anti-fading, stain-inhibiting or ultraviolet-absorbing agents include, for example, known compounds such as hydroquinones, hindered phenols, catechols, gallates, aminophenols, hindered amines, chromanols, indanes and ethers or esters of these compounds as formed by silylating, acylating or alkylating the phenolic hydroxyl group therein, as well as metal complexes.
However, although these compounds have some effect as an anti-fading or anti-discoloring agent for color images, they are still insufficient for meeting the customers' need of desiring to have color images with higher image quality. In addition, these compounds often vary the color hue of the color images formed or often cause fogging of the photographic materials containing them. Further, these compounds can not be dispersed well in the coating emulsion. Also, after the emulsion containing these compounds has been coated on a photographic support, the compounds often form fine crystals. For these reasons, the above-mentioned compounds are not totally favorable as practical additives to color photographic materials.
Use of hydrazine compounds having particular structures for prevention of fading and discoloration of color photographic materials has been proposed in, for example, JP-A-63-220142, JP-A-63-229455, JP-A-63-256951, JP-A-62-270954, JP-A-2-148035 and JP-A-2-141745. (The term "JP-A" as used herein means an "unexamined published Japanese patent application".) However, the compounds as described in these patent publications do not have sufficient anti-fading, anti-discoloring and anti-staining effects. JP-A-2-141745 has proposed the use of hydrazine compounds with cyan couplers. However, the compounds described therein are almost ineffective when used in combination with the couplers of the present invention. JP-A-1-147455 has proposed the use of hydrazine compounds for the purpose of preventing color fogging (e.g. coloration of non-exposed area) and color mixing and for the purpose of improving photographic characteristics such as graininess. However, the compounds described therein are also almost ineffective when used along with the couplers of the present invention. In addition, the compounds described in the above-mentioned patent publications often cause fogging or retard coloration of couplers, or have some other bad effects on photographic characteristics. Further, some of the compounds have poor solubility and can not be coated normally.
On the other hand, staining of the color image is one serious problem for color photographs. Stains are unfavorable since they impair the clarity of the images formed and additionally impair the visual sharpness of the color images formed. In particular, in reflective photographic materials such as color printing papers, since the reflection density of stains is to be emphasized to theoretically several times the transmission density thereof, even weak and fine stains are an extremely important factor in deteriorating the image quality of the images formed.
In general, both processed and non-processed silver halide color photographic materials containing cyan coupler(s) of formula (C-1) often have yellow to red stains after being stored for a long period of time either in a dark place or in a light place. Such staining is a fatal problem especially when cyan coupler(s) of formula (C-1) is/are introduced in reflective photographic materials such as color printing papers. Under this situation, therefore, development of a technique capable of effectively inhibiting fading, discoloration and staining of photographic color images formed without having any bad effects on photographic characteristics is desired.